Ambulatory Blood Pressure Monitoring System Research Articles

Revolutionizing Chronic Heart Disease Management: The Role of IoT-Based Ambulatory Blood Pressure Monitoring System.

Chronic heart disease (CHD) is a widespread and persistent health challenge that demands immediate attention. Early detection and accurate diagnosis are essential for effective treatment and management of this condition. To overcome this difficulty, we created a state-of-the-art IoT-Based Ambulatory Blood Pressure Monitoring System that provides real-time blood pressure readings, systolic, diastolic, and pulse rates at predefined intervals. This unique technology comes with a module that forecasts CHD's early warning score. Various machine learning algorithms employed comprise Naïve Bayes, K-Nearest Neighbors (K-NN), random forest, decision tree, and Support Vector Machine (SVM). Using Naïve Bayes, the proposed model has achieved an impressive 99.44% accuracy in predicting blood pressure, a vital aspect of real-time intensive care for CHD. This IoT-based ambulatory blood pressure monitoring (IABPM) system will provide some advancement in the field of healthcare. The system overcomes the limitations of earlier BP monitoring devices, significantly reduces healthcare costs, and efficiently detects irregularities in chronic heart diseases. By implementing this system, we can take a significant step forward in improving patient outcomes and reducing the global burden of CHD. The system's advanced features provide an accurate and reliable diagnosis that is essential for treating and managing CHD. Overall, this IoT-based ambulatory blood pressure monitoring system is an important tool for the early identification and treatment of CHD in the field of healthcare.

GENDER DIFFERENCES IN ARTERIAL STIFFNESS IN YOUNG PATIENTS WITH PRIMARY HYPERTENSION

Objective: Influence of sex hormones on regulation of arterial stiffness (AS) include different mechanisms where changes in extracellular matrix, smooth and endothelial cells, and influence on oxidative stress and chronic inflammation are highlighted. In women after puberty AS decreases what confirm selective and fluctuating effect of sex hormones, primarly estrogen. In older men, hypogonadism is associated with incresed AS, while testosterone replacement reduce pulse wave velocity (PWV). Our aim was to analyze difference in central hemodynamic parameters between men and women with stage 1 hypertension. Design and method: This study included 154 patients with the primary hypertnsion (69.5% women, mean age 38.5). In all of them we collected different data and antroplogical paramaters using medical records. Parameters of AS were measured with the office tonometric system (SphygmoCor) and 24h ambulatory blood pressure monitoring system using Mobil-o-Graph and Arteriograph, but also estimated PWV was calculated using validated equation (ePWV). Results: There were no statistically significant gender differences in PWV values measured in the office oCor, measured during 24 hours (using Arteriograph and Mobil-O-Graph), and ePWV. There were no statistically significant gender differences in the values of 24 hours systolic and diastolic central aortic pressure (CAP) (Arteriograph or Mobil-O-Graph). Women had significant higher office CAP Men, on average, had statistically significantly higher amplified pulse pressure (APP) values than women (144.20 vs. 128.94, t = 3.275, p < 0.01), while women had statistically significantly higher office augumentation index (AiX) values (t = -6.118, p < 0.001), as well 24 hours (Mobil- O-Graph (t = -5.940, p < 0.001;Arteriograph (t = -5.580, p < 0.001). Conclusions: Possible explanation of no statistically significant differences in PWV values between men and women is average age of our group. A possible gender difference in AiX can be consequence of the increased reflection of pulse waves, which is increased in women. Longitudinal study should be conducted with monitoring of patients at longer time intervals in order to determine the further hormonal influence on structure of the arteries and for the assesment of total CV risk.

Neutrophil and monocyte ratios to high-density lipoprotein cholesterol as biomarkers in non-dipping hypertension

ABSTRACT Objective To investigate the level and significance of neutrophils to high-density lipoprotein cholesterol ratio (NHR) and monocytes to high-density lipoprotein cholesterol ratio (MHR) in patients with non-dipping hypertension. Methods A total of 228 patients were retrospectively enrolled in the study. They were divided into the dipping hypertension group (n = 76), the non-dipping hypertension group (n = 77) and the control group (n = 75) according to 24-h ambulatory blood pressure monitoring system (ABPM) recordings. NHR and MHR were calculated and compared statistically. Receiver operating characteristic (ROC) curve analyses were performed for NHR and MHR. Binary logistic regression analyses were introduced to investigate the independent associations of NHR and MHR with non-dipping hypertension. Results The NHR and MHR were significantly higher in the non-dipping hypertension group compared with the control group (p = .001, p < .001, respectively) and the dipping hypertension group (p = .039, p = .003, respectively). According to ROC curve analyses, NHR>73.35 and MHR>7.54 were regarded as high-risk groups. The area under the curve (AUC) was 0.642 (p < .001) for NHR and 0.718 (p < .001) for MHR. In multivariate analysis, compared with NHR, only MHR was still recognized as a marker for detection of non-dipping hypertension (odds ratio [OR]: 1.208, 95% confidence interval [CI]: 1.076 to 1.356, p = .001). Conclusions Our data indicated that not NHR but MHR as new composite marker of inflammation and lipid metabolism may predict non-dipping hypertension to some extent.

Association of Abdominal Arterial Calcification Score with Patients' Survival and Kidney Allograft Function after Kidney Transplant.

Abdominal arterial calcification (AAC) is common among candidates for kidney transplant. The aim of this study is to correlate AAC score value with post-kidney transplant outcomes. We modified the coronary calcium score by changing the intake data points and used it to quantitate the AAC. We conducted a retrospective clinical study of all adult patients who were transplanted at our center, between 2010 and 2013, and had abdominal computed tomography scan done before transplantation. Outcomes included mortality, pulse pressure (PP) measured by 24h ambulatory blood pressure monitoring system, and kidney allograft function measured by iothalamate clearance. For each 1000 increase of AAC score value, there is an associated 1.05 increase in the risk of death (95% CI 1.02, 1.08) (p < 0.001). Overall median AAC value for all patients was 1784; Kaplan-Meier curve showed reduced survival of all-cause mortality for patients with AAC score value above median and reduced survival among patients with cardiac related mortality. The iothalamate clearance was lower among patients with total AAC score value above the median. Patients with abnormal PP (< 40 or > 60mmHg) had an elevated median AAC score value at 4319.3 (IQR 1210.4, 11097.1) compared to patients with normal PP with AAC score value at 595.9 (IQR 9.9, 2959.9) (p < 0.001). We showed an association of AAC with patients' survival and kidney allograft function after kidney transplant. The AAC score value could be used as a risk stratification when patients are considered for kidney transplant.

Knowledge-driven feature engineering to detect multiple symptoms using ambulatory blood pressure monitoring data

Background: Hypertension is a major health concern across the globe and needs to be properly diagnosed to so it can be treated and to mitigate for this critical health condition. In this context, ambulatory blood pressure monitoring is essential to provide for a proper diagnosis of hypertension, which may not be possible otherwise due to the white coat effect or masked hypertension. In this paper, the objective is to develop a model which incorporates expert’s knowledge in the feature engineering process so as to accurately predict multiple medical conditions. As a case study, we have considered multiple symptoms related to hypertension and used an ambulatory blood pressure monitoring method to continuously acquire hypertension relevant data from a patient. The goal is to train a model with a minimum set of the most effective knowledge-driven features which are useful to detect multiple symptoms simultaneously using multi-class classification techniques.Method: Artificial intelligence-based blood pressure monitoring techniques introduce a new dimension in the diagnosis of hypertension by enabling a continuous (24hours) analysis of systolic and diastolic blood pressure levels. In this work, we present a model that entails a knowledge-driven feature engineering method and implemented an ambulatory blood pressure monitoring system to diagnose multiple cardiac parameters and associated conditions simultaneously these include morning surge, circadian rhythm, and pulse pressure. The knowledge-driven features are extracted to improve the interpretability of the classification model and machine learning techniques (Random Forest, Naive Bayes, and KNN) were applied in a multi-label classification setup using RAkEL to classify multiple conditions simultaneously.Results: The results obtained (F 1 = 0.918) show that the Random forest technique has performed well for multilabel classification using knowledge-driven features. Our technique has also reduced the complexity of the model by reducing the number of features required to train a machine learning model.Conclusion: Considering these results, we conclude that knowledge-driven feature engineering enhances the learning process by reducing the number of features given as input to the machine learning algorithm. The proposed feature engineering method considers expert’s knowledge to develop better diagnosis models which are free from misleading data-driven noisy features in some situations. It is a white-box approach in which clinicians can under stand the importance of a feature while looking at its value.

The systolic to diastolic pressure ratio in non-dipping essential hypertension patients

Nocturnal blood-pressure (BP) decline or dipping is a physiological response in healthy BP-regulation; the lack of this adaptation is frequently observed in patients with essential hypertension (EH) [Chesebro,2020]. Involvement of autonomic dysregulation in EH may result in adrenergic overdrive [Mancia and Grassi,2014; Carthy, 2014]. Heart morphology [Henein, 2011] and systolic to diastolic pressure ratio (SDPR) were previously related to the harmony of the so-called golden ratio (GR = 1.618) [Yetkin, 2015]. We aimed here to identify patterns of circadian dysfunction in newly diagnosed patients with EH compared to individuals with normotensive individuals (NIs) by monitoring them with a non-invasive ambulatory blood pressure monitoring (ABPM) system and evaluating their SDPR.

Performance Evaluation of Internet of Things Prototype for Preeclampsia Monitoring in Antenatal Care

Globally, Preeclampsia has been an alarming condition, thus creating a major concern in its prevention and monitoring. Software developers have implemented several Internet of Things systems to transform human society towards becoming convenient and efficient with maternal health benefits. Due to the freedom in developing these systems, evaluation of the systems’ performance must be addressed to enable this revolutionized transformation. Therefore, the study selected an already developed 24-hour ambulatory blood pressure monitoring system for preeclampsia management in antenatal care to represent other IoT systems in conducting the performance evaluation. A sample of fifty pregnant mothers was selected using purposive and simple random sampling to conduct the performance evaluation. The study used a total of 200 blood pressure readings from pregnant mothers. Consistency, response rate, accuracy, reliability, and output were the metrics used to evaluate the IoT based system’s performance. During performance evaluation, the study found out that the system achieved all the functionalities expected in its assessment. Therefore, the IoT based system has the potential to inform future antenatal practices.

A 24-hour ambulatory blood pressure monitoring system for preeclampsia management in antenatal care

Abstract The burden of preeclampsia has been a major concern worldwide both in developed and developing countries, making its prevention and management a major concern. Although motherhood is a fulfilling experience in society, it is connected to ill-health in some women, leading to maternal morbidity and mortality. The United Nations' Sustainable Development Goal (SDG) 3 aims to reduce the global maternal mortality ratio to less than 70 per 100,000 live births. These deaths are caused by among other things, the emergence of conditions such as preeclampsia during pregnancy. Therefore, this study sought to implement a 24-hour ambulatory blood pressure monitoring solution for preeclampsia management, using a smartwatch in conjunction with a mobile and cloud-based application. Upon blood pressure readings from the expectant mother, an alert is sent to the assigned caregiver in order to initiate quick action. The researchers adopted a rapid prototyping approach in the implementation of the 24-hour ambulatory blood pressure monitoring system. An experimental design was adopted in the study to evaluate whether the system functionalities performed as expected. The system, which was evaluated in the context of a sample of 30 expectant mothers from two level 5 hospitals in Kenya, has been able to read blood pressure from expectant mothers' smartwatches. The real-time data is then sent to the caregivers’ smartphone, as well as an alert. The solution has shown great potential for actual adoption in healthcare systems in developing countries, given its simplicity and affordability.

Recurrent paroxysmal atrial fibrillation induced by marked hypoxia during sleep-disordered breathing

Sleep-disordered breathing (SDB) has a big impact on autonomic nervous activity and thus induces or deteriorates various cardiovascular diseases. We here describe a typical but rarely documented case which clearly indicates a strong link between SDB and cardiovascular disease. A 68-year-old woman complaining of frequent palpitations was referred to our institute. An electrocardiogram (ECG) at a previous clinic had shown atrial fibrillation, although it had already returned to sinus rhythm on arrival at our institute. Her body mass index was 32.5kg/m2 and she had a history of loud snoring. Simultaneous examinations of Holter ECG monitoring and ambulatory polysomnography (PSG) showed onset of paroxysmal atrial fibrillation following marked oxygen desaturation at midnight. In-hospital PSG revealed severe obstructive sleep apnea. A new device with desaturation triggered ambulatory blood pressure monitoring system performed 1 week later again showed a midnight onset of paroxysmal atrial fibrillation coincided with surge of blood pressure with marked desaturation. Her recurrence of palpitations had obviously decreased by continuous positive airway pressure therapy thereafter.<Learning objective: A clinician should suspect sleep-disordered breathing (SDB) behind cardiac arrhythmia, especially if it is nocturnal. Nocturnal hypertension especially in obese patients may indicate SDB. Successful therapy for SDB by such as continuous positive airway pressure therapy attenuates sympatho-excitation and would improve the result of treatment of the arrhythmia.>

Nocturnal blood pressure is associated with the progression of microvascular complications and hypertension in patients with type 1 diabetes mellitus

AimsTo evaluate relationships between early alterations in blood pressure and the progression of microvascular complications of diabetes in clinically-normotensive patients with type 1 diabetes (T1DM). MethodsIn a prospective observational study of 85 normotensive T1DM patients without microalbuminuria, blood pressure (BP) was monitored over 24h using the ambulatory blood pressure monitoring (ABPM) system at baseline and 7years later. Development or progression of microalbuminuria, retinopathy and hypertension was evaluated. ResultsInitially, 20 patients (24%) were diagnosed with masked hypertension and 31 (37%) with non-dipper pattern as the only pathological findings. At 7years: 1) twenty-seven patients (32%) had progression of retinopathy related to the nocturnal diastolic blood pressure (BPD) (OR:1.122; p=0.034) and final non-dipper pattern (OR:5.857; p=0.005); 2) seven patients (10%) developed microalbuminuria for which nocturnal systolic blood pressure (BPS) was a risk factor (OR:1.129; p=0.007); 3) five of the normotensive patients (9%) progressed to hypertension; historic HbA1c (OR:2.767; p=0.046) and nocturnal BPD (OR:1.243; p=0.046) being the related risk factors. BPD level ≥65mmHg was associated with an increase in progression of retinopathy and hypertension. ConclusionsIn T1DM patients there is an elevated prevalence of BP alterations, detected using ABPM. Alterations in nocturnal BP predispose to development/progression of microvascular complications and overt hypertension.

White coat hypertension in pediatrics.

The article summarizes current information on blood pressure changes in children during clinic visit. White coat as a general dressing of physicians and health care personnel has been widely accepted at the end of the 19th century. Two problems can be associated with the use of white coat: white coat phenomenon and white coat hypertension. Children often attribute pain and other unpleasant experience to the white coat and refuse afterwards cooperation with examinations. Definition of white coat hypertension in the literature is not uniform. It has been defined as elevated blood pressure in the hospital or clinic with normal blood pressure at home measured during the day by ambulatory blood pressure monitoring system. White coat effect is defined as temporary increase in blood pressure before and during visit in the clinic, regardless what the average daily ambulatory blood pressure values are. Clinical importance of white coat hypertension is mainly because of higher risk for cardiovascular accidents that are dependent on end organ damage (heart, vessels, kidney). Current data do not allow any clear recommendations for the treatment. Pharmacological therapy is usually started in the presence of hypertrophic left ventricle, changes in intimal/medial wall thickness of carotic arteries, microalbuminuria and other cardiovascular risk factors. Nonpharmacological therapy is less controversial and certainly more appropriate. Patients have to change their life style, need to eliminate as much cardiovascular risk factors as possible and sustain a regular blood pressure monitoring.

Increased nocturnal heart rate and wave reflection are early markers of cardiovascular disease in Williams–Beuren syndrome children

Williams-Beuren syndrome (WBS) is a genetic disorder that involves elastin gene causing cardiovascular abnormalities and increased risk. However, data on arterial function in these patients are only few and conflicting. Aim of this study was to evaluate dynamic behaviour of central and peripheral blood pressure (BP) and arterial stiffness parameters early in the course of WBS. We enrolled 19 WBS paediatric patients (age 13 ± 4 years) and 23 age, height and BP-matched controls (10 ± 4 years). We evaluated 24-h ambulatory BP values via an ambulatory blood pressure monitoring (ABPM) system (Mobil-O-Graph) also capable to calculate 24-h central BP and 24-h arterial stiffness parameters. Carotid-femoral PWV (cf-PWV) was assessed in all WBS individuals (Complior). BP values were similar in WBS and control, during the daytime and the night-time. The same behaviour applies to 24-h central BP. However, during the night, WBS showed heart rate values (HR; 78 ± 10 vs. 71 ± 9 bpm; P < 0.03), augmentation index (Aix; 24.6 ± 13.5% vs. 16.5 ± 8.9%; P = 0.03) and reflection magnitude (68 5.8 vs. 63.5 8.1; P = 0.02) higher than controls. The HR, Aix and reflection magnitude reduction in the day-night shift was lower in WBS than in controls. Cf-PWV in WBS children did not differ when compared with their normalized expected value. In WBS children, the higher night-time HR, Aix and reflection magnitude and their impaired physiological reduction in the day-night shift suggests an abnormal sympathetic cardiovascular control, an augmented wave reflection and an increase in small arteries resistance. These alterations possibly due to a sympathetic overactivity can be regarded as earlier hallmarks of cardiovascular dysfunction in these patients.

Haemodynamic responses to tobacco smoke inhalation in male adolescents in Lusaka, Zambia.

Tobacco smoke causes changes in the levels of catecholamines in the blood. This leads to an increase in blood pressure and heart rate. This is due to nicotine which has also been noted to cause a decrease in vasodilatory activities leading to an increase in both the blood pressure and heart rate. To determine the acute effects of tobacco smoke on haemodynamics in black male adolescents in Lusaka, Zambia. This was an observational study done at the University of Zambia School of Medicine Cardiovascular Research Laboratory in the month of December, 2014. Twenty-two (22) black, male-adolescent (age range 19-25 years), active-smokers, consented to participate in the study. The Diasys Ambulatory Blood Pressure Monitoring system (Novacor, France) was used to obtain the Systolic and Diastolic blood pressures (SBP and DBP) and the heart rate. These were obtained 15 minutes before smoking at 5 minute intervals and averaged to obtain the baseline, during the 15 minutes of smoking and on immediate cessation of smoking and thereafter every 15 minutes up to an hour after smoking. There was a significant rise in SBP (mmHg) during smoking (127.9 ± 13.80 mmHg) from baseline values (113.5 ± 13.15 mmHg) (P = .00). It took 30 minutes for the SBP to return to baseline after cessation of smoking. DBP (mmHg) also increased from baseline (79.5 ± 8.79 mmHg) to 85.6 ± 10.92 mmHg during smoking (P = .01). It returned to baseline values immediately after cessation of smoking. The heart rate (bpm) was also noted to significantly increase during smoking (95.2 ± 16.72 bpm) from the values noted before smoking (74.3 ± 13.75 bpm) (P = .05). The mean value for heart rate returned to baseline value by the 15th minute of recovery. The present study demonstrates that smoking may be the cause for the acute increases in SBP, DBP and heart rate in smokers. The smoking caused significant increases in all the haemodynamic indices considered in this study within 15 minutes. Both SBP and DBP increase are indices for stroke and coronary heart disease respectively. The effect of increased SBP was noted to last for 30 minutes while DBP returned to baseline immediately after smoking. A significant increase in heart rate was also noted in the study.

The investigation of exercise-induced fatigue on pesticide spraying operation

To evaluate the exercise-induced fatigue in operators during pesticide spraying based on surface electromyography (sEMC) signals and heart rate. The sEMG signals were recorded from the right trapezius, biceps brachii, extensor digitorum, and flexor digitorum of 19 operators by portable electromyography units during pesticide spraying using 3WS-16 manual sprayers. Meanwhile, the heart rate of operators was measured by the ambulatory blood pressure monitoring system. The changes in median frequency and heart rate were analyzed. Pesticide spraying was defined as low-intensity labor. The median frequency of the right trapezius, biceps brachii, extensor digitorum, and flexor digitorum decreased significantly as pesticide spraying went on (P < 0.05). The body remained in a state of slight fatigue from 8 min after pesticide spraying began to the end of the operation. The degree of exercise-induced fatigue of operators can be evaluated based on sEMG signals and heart rate during pesticide spraying.

Does family history of metabolic syndrome affect the metabolic profile phenotype in young healthy individuals?

BackgroundEarly identification of high-risk individuals is key for the prevention of cardiovascular disease (CVD). The aim of this study was to assess the potential impact of a family history of metabolic syndrome (fhMetS) on the risk of metabolic disorders (abnormal body mass, lipid profile, glucose metabolism, insulin resistance, and blood pressure) in healthy young individuals.MethodsWe studied CVD risk factors in 90 healthy volunteers, aged 27–39 years; of these, 78 had fhMetS and 12 were without fhMetS (control group). Fasting serum lipids, glucose, and insulin levels were assayed, and anthropometric parameters and blood pressure using, an ambulatory blood pressure monitoring system, were measured. Nutritional and physical activity habits were assessed.ResultsDespite similar nutritional and physical activity habits, abnormal body mass was found in 53.2% of the fhMetS participants and 46.1% of the control participants (p = 0.54). The occurrence of obesity was 19.4% and 0%, respectively (p = 0.69). Compared to the control participants, fhMetS was associated with significantly higher total cholesterol (5.46 mmol/L vs. 4.69 mmol/L, p < 0.030), low-density lipoprotein cholesterol ( 3.28 mmol/L vs. 2.90 mmol/L, p < 0.032), and non-high-density lipoprotein cholesterol ( 3.74 mmol/L vs. 3.25 mmol/L, p < 0.016) levels, in addition to lower fasting glucose levels ( 4.51 mmol/L vs. 4.81 mmol/L, p < 0.042). A positive correlation between fasting glucose and insulin levels (r = 0.28; p < 0.015) was detected in the fhMetS participants. Higher mean daytime systolic blood pressure (121.5 mmHg vs. 113.3 mmHg, p < 0.035), mean daytime diastolic blood pressure ( 79.0 mmHg vs. 74.5 mmHg, p < 0.045), and mean nighttime diastolic blood pressure ( 64.0 mmHg vs. 59.5 mmHg, p < 0.019) were observed in the fhMetS group.ConclusionsMore than 50% of the fhMetS participants had excess weight or a lipid disorder, which may indicate an increased risk of cardiovascular disease and the need for regular ambulatory assessment of serum lipid concentrations in young people with a family history of MetS.

Validation of the integration of technology that measures additional "vascular" indices into an ambulatory blood pressure monitoring system.

BackgroundThe objective of this study was to validate the novel integration of oscillometric (Vasotens®) technology into a BPLab® ambulatory blood pressure (BP) monitoring system to measure central BP, the aortic augmentation index, and pulse wave velocity (PWV) compared with the recommended and widely accepted tonometric method.MethodsThe ARTERY Society guidelines for comparison of PWV measurement techniques were used as the basis for recruitment of 99 individuals (mean age 44±19 years, 52 males). The standard for comparison was the conventional “classic” SphygmoCor device.ResultsAccordance of the two methods was satisfactory (r=0.98, mean difference of 2.9±3.5 mmHg for central systolic BP; r=0.98, mean difference of −1.1±2.3 mmHg for central diastolic BP; r=0.83, mean difference of −2.6%±13% for aortic augmentation index; r=0.85, mean difference of 0.69±1.4 for PWV).ConclusionThe performance of Vasotens algorithms using an oscillometric ambulatory BP monitoring system is feasible for accurate diagnosis, risk assessment, and evaluation of the effects of antihypertensive drugs.

Commentary: Revisiting the Early Morning Blood Pressure Surge and Myocardial Ischemia

In this issue of the Journal, Uen and colleagues’ article entitled ‘‘Early Morning Surge and Dipping Status of Blood Pressure: Are These of Predictive Value for Silent Myocardial Ischemia?’’ revisits the entity of circadian rhythms and coronary ischemia. In their study, the group evaluated 76 patients of 344 who demonstrated ST depression on 24-hour monitoring for ST-segment characteristics and blood pressure (BP). They determined that the degree of overnight BP dipping and concomitant early morning BP surge did not correlate with the presence of ST-segment depression indicative of myocardial ischemia. Notable within the data presented, but not specifically addressed by the authors in the discussion section, is the fact that in all of the time frames measured with the ambulatory BP monitoring system, the patients who did not demonstrate ST depression during the course of the day had statistically significantly lower mean systolic BP. Therefore, the most important fact to arise from these authors’ work is that overall BP control is more predictive of silent ischemia than either overnight BP dipping or early morning surges. The presence of a morning peak for acute myocardial infarction (MI) has been noted for decades but was disregarded from the earliest papers as being a reporting bias from patients sleeping through their symptoms. The Multicenter Investigation of Limitation of Infarct Size (MILIS) study demonstrated an increase in cardiac events during the hours of 6 am to 12 noon, utilizing time to peak creatinine kinase–MB fraction to determine the time of onset for the MI. A second study, the Intravenous Streptokinase in Acute Myocardial Infarction (ISAM) trial corroborated these results in more than 1700 patients, demonstrating a 4-fold greater likelihood of events between 8 am and 9 am compared with overnight hours. Similar patterns have emerged in patients presenting with sudden cardiac death (SCD) in several studies. There are several physiologic events demonstrating circadian rhythms that could account for the morning peak in acute ischemic cardiac events. There is an increase in sympathetic activity that accompanies and readies the body for awakening in the morning. Coincident with this is a rise in BP, pulse pressure, and heart rate, which may increase the hemodynamic stresses across the coronary arteries, most notably at the shoulder regions of the vulnerable plaques. Additionally, higher sympathetic tone may promote increased vascular tone and coronary vasoconstriction, while increasing metabolic demands on the myocardium. Furthermore, there is an early morning increase in platelet aggregability and a reduction in the fibrinolytic From the Cardiology Division, Department of Internal Medicine, University of Rochester Medical Center, Rochester, NY 14642 Address for correspondence: John D. Bisognano, MD, PhD, Cardiology Division, Department of Internal Medicine, University of Rochester, 601 Elmwood Avenue, Box 679-7, Rochester, NY 14642-8679 E-mail: john_bisognano@urmc.rochester.edu Manuscript received May 18, 2009; accepted May 22, 2009

Efficacy and safety of acarbose in the treatment of elderly patients with postprandial hypotension

Postprandial hypotension (PPH) occurs frequently in elderly people and may lead to syncope, falls, dizziness, weakness, angina pectoris, and stroke. Some studies suggest that the magnitude of the postprandial fall in blood pressure (BP) is influenced by the rate at which glucose enters the small intestine. We hypothesized that acarbose (alpha-glucosidase inhibitor), a hypoglycemic agent that decreases the rate of glucose absorption in the small intestine, would attenuate PPH in the elderly, and would be safe in the treatment. Forty-three elderly in-patients with PPH were recruited. All of them were in relatively stable conditions. They had semi-liquid standard meals without and with acarbose for the two following days: screening day and intervention day. Blood pressure and heart rate (HR) were recorded at baseline and every 15 minutes for 120 minutes using a non-invasive ambulatory blood pressure monitoring system during the study, and ejection fraction (EF) and fractional shortening (FS) were measured by two dimensional echocardiography. Compared with the screening day, the falls in systolic, diastolic and mean arterial blood pressure (SBP, DBP, MAP) (all P < 0.05) were significantly attenuated after taking acarbose during breakfast, so were MAP (P < 0.05) during lunch, DBP (P < 0.05) and MAP (P < 0.05) during supper. The change of HR was not statistically significant after taking acarbose in three meals. EF and FS were positively correlated with the relief rate. The effective power was 63%, and the incidence of adverse drug reaction (ADR) was 9%. Acarbose is effective and safe in the treatment of elderly patients with PPH.

How do the anti-hypertensive drugs influence the relationship between blood pressure and physical activity

Essential hypertensive patients have a good relationship between systolic blood pressure (SBP) and physical activity (PA) when treating with calcium channel blockers (CCB), angiotensin converting enzyme inhibitors (ACEI), angiotensin 2 receptor blockers (ARB) and diuretics (D). The aim of this study is to evaluate whether there are the differences in SBP-PA relationship when the patients are treated with different anti-hypertensive drugs. The hypertensive patients treating with CCB (n=32), ACEI (n=23), ARB (n=24) and D (n=13) were participated in this study. The mean age was 58 years in CCB, 60 in ACEI, 58 in ARB and 60 in D. there were no differences in age among the groups. The 24-hour ambulatory blood pressure monitoring (ABPM) system and activetracer for measuring PA were fitted simultaneously to these patients treating with the drugs. The relationship between SBP and PA was analyzed with single regression analysis (y=ax+b). The obtained correlation coefficients (r), “a” and “b” were compared by the analysis of variance (ANOVA). There were no differences in the value of “r” among CCB (0.48), ACEI (0.54), ARB (0.54) and D (0.56). There were no differences in the value of “a” among CCB (0.07), ACEI (0.07), ARB (0.07) and D (0.11). There were no differences in the value of “b” among CCB (133), ACEI (129), ARB (134) and D (132). The hypertensive patients treating with CCB, ACEI, ARB and D have the good relationship between SBP and PA. The values of “r”, “a” and “b” were same regardless of the anti-hypertensive drugs. The anti-hypertensive drugs (CCB, ACEI, ARB and D) reduced blood pressure with the same relationship between systolic blood pressure and physical activity.

Assessing the prognostic relevance of blood pressure variability: discrepant information from different indices

Assessing the prognostic relevance of blood pressure variability: discrepant information from different indices